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1 /* crypto/rand/md_rand.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3  * All rights reserved.
4  *
5  * This package is an SSL implementation written
6  * by Eric Young (eay@cryptsoft.com).
7  * The implementation was written so as to conform with Netscapes SSL.
8  *
9  * This library is free for commercial and non-commercial use as long as
10  * the following conditions are aheared to.  The following conditions
11  * apply to all code found in this distribution, be it the RC4, RSA,
12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13  * included with this distribution is covered by the same copyright terms
14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15  *
16  * Copyright remains Eric Young's, and as such any Copyright notices in
17  * the code are not to be removed.
18  * If this package is used in a product, Eric Young should be given attribution
19  * as the author of the parts of the library used.
20  * This can be in the form of a textual message at program startup or
21  * in documentation (online or textual) provided with the package.
22  *
23  * Redistribution and use in source and binary forms, with or without
24  * modification, are permitted provided that the following conditions
25  * are met:
26  * 1. Redistributions of source code must retain the copyright
27  *    notice, this list of conditions and the following disclaimer.
28  * 2. Redistributions in binary form must reproduce the above copyright
29  *    notice, this list of conditions and the following disclaimer in the
30  *    documentation and/or other materials provided with the distribution.
31  * 3. All advertising materials mentioning features or use of this software
32  *    must display the following acknowledgement:
33  *    "This product includes cryptographic software written by
34  *     Eric Young (eay@cryptsoft.com)"
35  *    The word 'cryptographic' can be left out if the rouines from the library
36  *    being used are not cryptographic related :-).
37  * 4. If you include any Windows specific code (or a derivative thereof) from
38  *    the apps directory (application code) you must include an acknowledgement:
39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40  *
41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51  * SUCH DAMAGE.
52  *
53  * The licence and distribution terms for any publically available version or
54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
55  * copied and put under another distribution licence
56  * [including the GNU Public Licence.]
57  */
58 /* ====================================================================
59  * Copyright (c) 1998-2001 The OpenSSL Project.  All rights reserved.
60  *
61  * Redistribution and use in source and binary forms, with or without
62  * modification, are permitted provided that the following conditions
63  * are met:
64  *
65  * 1. Redistributions of source code must retain the above copyright
66  *    notice, this list of conditions and the following disclaimer.
67  *
68  * 2. Redistributions in binary form must reproduce the above copyright
69  *    notice, this list of conditions and the following disclaimer in
70  *    the documentation and/or other materials provided with the
71  *    distribution.
72  *
73  * 3. All advertising materials mentioning features or use of this
74  *    software must display the following acknowledgment:
75  *    "This product includes software developed by the OpenSSL Project
76  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
77  *
78  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
79  *    endorse or promote products derived from this software without
80  *    prior written permission. For written permission, please contact
81  *    openssl-core@openssl.org.
82  *
83  * 5. Products derived from this software may not be called "OpenSSL"
84  *    nor may "OpenSSL" appear in their names without prior written
85  *    permission of the OpenSSL Project.
86  *
87  * 6. Redistributions of any form whatsoever must retain the following
88  *    acknowledgment:
89  *    "This product includes software developed by the OpenSSL Project
90  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
91  *
92  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
93  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
94  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
95  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
96  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
97  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
98  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
99  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
100  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
101  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
102  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
103  * OF THE POSSIBILITY OF SUCH DAMAGE.
104  * ====================================================================
105  *
106  * This product includes cryptographic software written by Eric Young
107  * (eay@cryptsoft.com).  This product includes software written by Tim
108  * Hudson (tjh@cryptsoft.com).
109  *
110  */
111 
112 #define OPENSSL_FIPSEVP
113 
114 #ifdef MD_RAND_DEBUG
115 # ifndef NDEBUG
116 #   define NDEBUG
117 # endif
118 #endif
119 
120 #include <assert.h>
121 #include <stdio.h>
122 #include <string.h>
123 
124 #include "e_os.h"
125 
126 #include <openssl/crypto.h>
127 #include <openssl/rand.h>
128 #include "rand_lcl.h"
129 
130 #include <openssl/err.h>
131 
132 #ifdef BN_DEBUG
133 # define PREDICT
134 #endif
135 
136 /* #define PREDICT	1 */
137 
138 #define STATE_SIZE	1023
139 static int state_num=0,state_index=0;
140 static unsigned char state[STATE_SIZE+MD_DIGEST_LENGTH];
141 static unsigned char md[MD_DIGEST_LENGTH];
142 static long md_count[2]={0,0};
143 static double entropy=0;
144 static int initialized=0;
145 
146 static unsigned int crypto_lock_rand = 0; /* may be set only when a thread
147                                            * holds CRYPTO_LOCK_RAND
148                                            * (to prevent double locking) */
149 /* access to lockin_thread is synchronized by CRYPTO_LOCK_RAND2 */
150 static CRYPTO_THREADID locking_threadid; /* valid iff crypto_lock_rand is set */
151 
152 
153 #ifdef PREDICT
154 int rand_predictable=0;
155 #endif
156 
157 const char RAND_version[]="RAND" OPENSSL_VERSION_PTEXT;
158 
159 static void ssleay_rand_cleanup(void);
160 static void ssleay_rand_seed(const void *buf, int num);
161 static void ssleay_rand_add(const void *buf, int num, double add_entropy);
162 static int ssleay_rand_bytes(unsigned char *buf, int num, int pseudo);
163 static int ssleay_rand_nopseudo_bytes(unsigned char *buf, int num);
164 static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num);
165 static int ssleay_rand_status(void);
166 
167 RAND_METHOD rand_ssleay_meth={
168 	ssleay_rand_seed,
169 	ssleay_rand_nopseudo_bytes,
170 	ssleay_rand_cleanup,
171 	ssleay_rand_add,
172 	ssleay_rand_pseudo_bytes,
173 	ssleay_rand_status
174 	};
175 
RAND_SSLeay(void)176 RAND_METHOD *RAND_SSLeay(void)
177 	{
178 	return(&rand_ssleay_meth);
179 	}
180 
ssleay_rand_cleanup(void)181 static void ssleay_rand_cleanup(void)
182 	{
183 	OPENSSL_cleanse(state,sizeof(state));
184 	state_num=0;
185 	state_index=0;
186 	OPENSSL_cleanse(md,MD_DIGEST_LENGTH);
187 	md_count[0]=0;
188 	md_count[1]=0;
189 	entropy=0;
190 	initialized=0;
191 	}
192 
ssleay_rand_add(const void * buf,int num,double add)193 static void ssleay_rand_add(const void *buf, int num, double add)
194 	{
195 	int i,j,k,st_idx;
196 	long md_c[2];
197 	unsigned char local_md[MD_DIGEST_LENGTH];
198 	EVP_MD_CTX m;
199 	int do_not_lock;
200 
201 	/*
202 	 * (Based on the rand(3) manpage)
203 	 *
204 	 * The input is chopped up into units of 20 bytes (or less for
205 	 * the last block).  Each of these blocks is run through the hash
206 	 * function as follows:  The data passed to the hash function
207 	 * is the current 'md', the same number of bytes from the 'state'
208 	 * (the location determined by in incremented looping index) as
209 	 * the current 'block', the new key data 'block', and 'count'
210 	 * (which is incremented after each use).
211 	 * The result of this is kept in 'md' and also xored into the
212 	 * 'state' at the same locations that were used as input into the
213          * hash function.
214 	 */
215 
216 	/* check if we already have the lock */
217 	if (crypto_lock_rand)
218 		{
219 		CRYPTO_THREADID cur;
220 		CRYPTO_THREADID_current(&cur);
221 		CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
222 		do_not_lock = !CRYPTO_THREADID_cmp(&locking_threadid, &cur);
223 		CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
224 		}
225 	else
226 		do_not_lock = 0;
227 
228 	if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
229 	st_idx=state_index;
230 
231 	/* use our own copies of the counters so that even
232 	 * if a concurrent thread seeds with exactly the
233 	 * same data and uses the same subarray there's _some_
234 	 * difference */
235 	md_c[0] = md_count[0];
236 	md_c[1] = md_count[1];
237 
238 	memcpy(local_md, md, sizeof md);
239 
240 	/* state_index <= state_num <= STATE_SIZE */
241 	state_index += num;
242 	if (state_index >= STATE_SIZE)
243 		{
244 		state_index%=STATE_SIZE;
245 		state_num=STATE_SIZE;
246 		}
247 	else if (state_num < STATE_SIZE)
248 		{
249 		if (state_index > state_num)
250 			state_num=state_index;
251 		}
252 	/* state_index <= state_num <= STATE_SIZE */
253 
254 	/* state[st_idx], ..., state[(st_idx + num - 1) % STATE_SIZE]
255 	 * are what we will use now, but other threads may use them
256 	 * as well */
257 
258 	md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0);
259 
260 	if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
261 
262 	EVP_MD_CTX_init(&m);
263 	for (i=0; i<num; i+=MD_DIGEST_LENGTH)
264 		{
265 		j=(num-i);
266 		j=(j > MD_DIGEST_LENGTH)?MD_DIGEST_LENGTH:j;
267 
268 		MD_Init(&m);
269 		MD_Update(&m,local_md,MD_DIGEST_LENGTH);
270 		k=(st_idx+j)-STATE_SIZE;
271 		if (k > 0)
272 			{
273 			MD_Update(&m,&(state[st_idx]),j-k);
274 			MD_Update(&m,&(state[0]),k);
275 			}
276 		else
277 			MD_Update(&m,&(state[st_idx]),j);
278 
279 		/* DO NOT REMOVE THE FOLLOWING CALL TO MD_Update()! */
280 		MD_Update(&m,buf,j);
281 		/* We know that line may cause programs such as
282 		   purify and valgrind to complain about use of
283 		   uninitialized data.  The problem is not, it's
284 		   with the caller.  Removing that line will make
285 		   sure you get really bad randomness and thereby
286 		   other problems such as very insecure keys. */
287 
288 		MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
289 		MD_Final(&m,local_md);
290 		md_c[1]++;
291 
292 		buf=(const char *)buf + j;
293 
294 		for (k=0; k<j; k++)
295 			{
296 			/* Parallel threads may interfere with this,
297 			 * but always each byte of the new state is
298 			 * the XOR of some previous value of its
299 			 * and local_md (itermediate values may be lost).
300 			 * Alway using locking could hurt performance more
301 			 * than necessary given that conflicts occur only
302 			 * when the total seeding is longer than the random
303 			 * state. */
304 			state[st_idx++]^=local_md[k];
305 			if (st_idx >= STATE_SIZE)
306 				st_idx=0;
307 			}
308 		}
309 	EVP_MD_CTX_cleanup(&m);
310 
311 	if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
312 	/* Don't just copy back local_md into md -- this could mean that
313 	 * other thread's seeding remains without effect (except for
314 	 * the incremented counter).  By XORing it we keep at least as
315 	 * much entropy as fits into md. */
316 	for (k = 0; k < (int)sizeof(md); k++)
317 		{
318 		md[k] ^= local_md[k];
319 		}
320 	if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */
321 	    entropy += add;
322 	if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
323 
324 #if !defined(OPENSSL_THREADS) && !defined(OPENSSL_SYS_WIN32)
325 	assert(md_c[1] == md_count[1]);
326 #endif
327 	}
328 
ssleay_rand_seed(const void * buf,int num)329 static void ssleay_rand_seed(const void *buf, int num)
330 	{
331 	ssleay_rand_add(buf, num, (double)num);
332 	}
333 
ssleay_rand_bytes(unsigned char * buf,int num,int pseudo)334 static int ssleay_rand_bytes(unsigned char *buf, int num, int pseudo)
335 	{
336 	static volatile int stirred_pool = 0;
337 	int i,j,k,st_num,st_idx;
338 	int num_ceil;
339 	int ok;
340 	long md_c[2];
341 	unsigned char local_md[MD_DIGEST_LENGTH];
342 	EVP_MD_CTX m;
343 #ifndef GETPID_IS_MEANINGLESS
344 	pid_t curr_pid = getpid();
345 #endif
346 	int do_stir_pool = 0;
347 
348 #ifdef PREDICT
349 	if (rand_predictable)
350 		{
351 		static unsigned char val=0;
352 
353 		for (i=0; i<num; i++)
354 			buf[i]=val++;
355 		return(1);
356 		}
357 #endif
358 
359 	if (num <= 0)
360 		return 1;
361 
362 	EVP_MD_CTX_init(&m);
363 	/* round upwards to multiple of MD_DIGEST_LENGTH/2 */
364 	num_ceil = (1 + (num-1)/(MD_DIGEST_LENGTH/2)) * (MD_DIGEST_LENGTH/2);
365 
366 	/*
367 	 * (Based on the rand(3) manpage:)
368 	 *
369 	 * For each group of 10 bytes (or less), we do the following:
370 	 *
371 	 * Input into the hash function the local 'md' (which is initialized from
372 	 * the global 'md' before any bytes are generated), the bytes that are to
373 	 * be overwritten by the random bytes, and bytes from the 'state'
374 	 * (incrementing looping index). From this digest output (which is kept
375 	 * in 'md'), the top (up to) 10 bytes are returned to the caller and the
376 	 * bottom 10 bytes are xored into the 'state'.
377 	 *
378 	 * Finally, after we have finished 'num' random bytes for the
379 	 * caller, 'count' (which is incremented) and the local and global 'md'
380 	 * are fed into the hash function and the results are kept in the
381 	 * global 'md'.
382 	 */
383 
384 	CRYPTO_w_lock(CRYPTO_LOCK_RAND);
385 
386 	/* prevent ssleay_rand_bytes() from trying to obtain the lock again */
387 	CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
388 	CRYPTO_THREADID_current(&locking_threadid);
389 	CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
390 	crypto_lock_rand = 1;
391 
392 	if (!initialized)
393 		{
394 		RAND_poll();
395 		initialized = 1;
396 		}
397 
398 	if (!stirred_pool)
399 		do_stir_pool = 1;
400 
401 	ok = (entropy >= ENTROPY_NEEDED);
402 	if (!ok)
403 		{
404 		/* If the PRNG state is not yet unpredictable, then seeing
405 		 * the PRNG output may help attackers to determine the new
406 		 * state; thus we have to decrease the entropy estimate.
407 		 * Once we've had enough initial seeding we don't bother to
408 		 * adjust the entropy count, though, because we're not ambitious
409 		 * to provide *information-theoretic* randomness.
410 		 *
411 		 * NOTE: This approach fails if the program forks before
412 		 * we have enough entropy. Entropy should be collected
413 		 * in a separate input pool and be transferred to the
414 		 * output pool only when the entropy limit has been reached.
415 		 */
416 		entropy -= num;
417 		if (entropy < 0)
418 			entropy = 0;
419 		}
420 
421 	if (do_stir_pool)
422 		{
423 		/* In the output function only half of 'md' remains secret,
424 		 * so we better make sure that the required entropy gets
425 		 * 'evenly distributed' through 'state', our randomness pool.
426 		 * The input function (ssleay_rand_add) chains all of 'md',
427 		 * which makes it more suitable for this purpose.
428 		 */
429 
430 		int n = STATE_SIZE; /* so that the complete pool gets accessed */
431 		while (n > 0)
432 			{
433 #if MD_DIGEST_LENGTH > 20
434 # error "Please adjust DUMMY_SEED."
435 #endif
436 #define DUMMY_SEED "...................." /* at least MD_DIGEST_LENGTH */
437 			/* Note that the seed does not matter, it's just that
438 			 * ssleay_rand_add expects to have something to hash. */
439 			ssleay_rand_add(DUMMY_SEED, MD_DIGEST_LENGTH, 0.0);
440 			n -= MD_DIGEST_LENGTH;
441 			}
442 		if (ok)
443 			stirred_pool = 1;
444 		}
445 
446 	st_idx=state_index;
447 	st_num=state_num;
448 	md_c[0] = md_count[0];
449 	md_c[1] = md_count[1];
450 	memcpy(local_md, md, sizeof md);
451 
452 	state_index+=num_ceil;
453 	if (state_index > state_num)
454 		state_index %= state_num;
455 
456 	/* state[st_idx], ..., state[(st_idx + num_ceil - 1) % st_num]
457 	 * are now ours (but other threads may use them too) */
458 
459 	md_count[0] += 1;
460 
461 	/* before unlocking, we must clear 'crypto_lock_rand' */
462 	crypto_lock_rand = 0;
463 	CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
464 
465 	while (num > 0)
466 		{
467 		/* num_ceil -= MD_DIGEST_LENGTH/2 */
468 		j=(num >= MD_DIGEST_LENGTH/2)?MD_DIGEST_LENGTH/2:num;
469 		num-=j;
470 		MD_Init(&m);
471 #ifndef GETPID_IS_MEANINGLESS
472 		if (curr_pid) /* just in the first iteration to save time */
473 			{
474 			MD_Update(&m,(unsigned char*)&curr_pid,sizeof curr_pid);
475 			curr_pid = 0;
476 			}
477 #endif
478 		MD_Update(&m,local_md,MD_DIGEST_LENGTH);
479 		MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
480 
481 #ifndef PURIFY /* purify complains */
482 		/* The following line uses the supplied buffer as a small
483 		 * source of entropy: since this buffer is often uninitialised
484 		 * it may cause programs such as purify or valgrind to
485 		 * complain. So for those builds it is not used: the removal
486 		 * of such a small source of entropy has negligible impact on
487 		 * security.
488 		 */
489 		MD_Update(&m,buf,j);
490 #endif
491 
492 		k=(st_idx+MD_DIGEST_LENGTH/2)-st_num;
493 		if (k > 0)
494 			{
495 			MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2-k);
496 			MD_Update(&m,&(state[0]),k);
497 			}
498 		else
499 			MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2);
500 		MD_Final(&m,local_md);
501 
502 		for (i=0; i<MD_DIGEST_LENGTH/2; i++)
503 			{
504 			state[st_idx++]^=local_md[i]; /* may compete with other threads */
505 			if (st_idx >= st_num)
506 				st_idx=0;
507 			if (i < j)
508 				*(buf++)=local_md[i+MD_DIGEST_LENGTH/2];
509 			}
510 		}
511 
512 	MD_Init(&m);
513 	MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
514 	MD_Update(&m,local_md,MD_DIGEST_LENGTH);
515 	CRYPTO_w_lock(CRYPTO_LOCK_RAND);
516 	MD_Update(&m,md,MD_DIGEST_LENGTH);
517 	MD_Final(&m,md);
518 	CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
519 
520 	EVP_MD_CTX_cleanup(&m);
521 	if (ok)
522 		return(1);
523 	else if (pseudo)
524 		return 0;
525 	else
526 		{
527 		RANDerr(RAND_F_SSLEAY_RAND_BYTES,RAND_R_PRNG_NOT_SEEDED);
528 		ERR_add_error_data(1, "You need to read the OpenSSL FAQ, "
529 			"http://www.openssl.org/support/faq.html");
530 		return(0);
531 		}
532 	}
533 
ssleay_rand_nopseudo_bytes(unsigned char * buf,int num)534 static int ssleay_rand_nopseudo_bytes(unsigned char *buf, int num)
535 	{
536 	return ssleay_rand_bytes(buf, num, 0);
537 	}
538 
539 /* pseudo-random bytes that are guaranteed to be unique but not
540    unpredictable */
ssleay_rand_pseudo_bytes(unsigned char * buf,int num)541 static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num)
542 	{
543 	return ssleay_rand_bytes(buf, num, 1);
544 	}
545 
ssleay_rand_status(void)546 static int ssleay_rand_status(void)
547 	{
548 	CRYPTO_THREADID cur;
549 	int ret;
550 	int do_not_lock;
551 
552 	CRYPTO_THREADID_current(&cur);
553 	/* check if we already have the lock
554 	 * (could happen if a RAND_poll() implementation calls RAND_status()) */
555 	if (crypto_lock_rand)
556 		{
557 		CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
558 		do_not_lock = !CRYPTO_THREADID_cmp(&locking_threadid, &cur);
559 		CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
560 		}
561 	else
562 		do_not_lock = 0;
563 
564 	if (!do_not_lock)
565 		{
566 		CRYPTO_w_lock(CRYPTO_LOCK_RAND);
567 
568 		/* prevent ssleay_rand_bytes() from trying to obtain the lock again */
569 		CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
570 		CRYPTO_THREADID_cpy(&locking_threadid, &cur);
571 		CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
572 		crypto_lock_rand = 1;
573 		}
574 
575 	if (!initialized)
576 		{
577 		RAND_poll();
578 		initialized = 1;
579 		}
580 
581 	ret = entropy >= ENTROPY_NEEDED;
582 
583 	if (!do_not_lock)
584 		{
585 		/* before unlocking, we must clear 'crypto_lock_rand' */
586 		crypto_lock_rand = 0;
587 
588 		CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
589 		}
590 
591 	return ret;
592 	}
593